Mismatched Subwoofers - OK or not?

[derrickdj1]

1 hour ago, Skillz4lif said:

I was going to ask this question, not with mismatched brands but with subs that fire in different directions. Do the same rules apply? I currently have a SW-450 and I'm looking at buying something else. The 450 fires down, so should I look for another down firing sub?

I have 8 sub spread around the room.  A distributed bass system will give the best and smoothes FR for the room.  Four is the usual number recommend for max benefit.  If anyone is thinking about 4 or more subs, Omnimic or REW is recommended as well as additional DSP such as, the I Nuke DSP amps or the Mini DSP.

 

I use five different type of subs in the HT and all different size.  The key is getting them into phase.  There is help on the forum once you are ready to go with setting up the subs.

[RoboKlipsch]

I think an important consideration is to understand that when you mix together subs of varying capabilities, your end result will likely be some form of "average" between them.

 

So if you are trying to integrate a big sub that rolls off below 20hz, with a small sub that rolls off at 35hz, your end result will NOT be a frequency curve that is flat to 20hz with more output. No, you will instead have a result where because of the limits of the 35hz sub, the end result will be output flat to a point in between the two.  While you can often tweak this somewhat with PEQ, gains and placement, in the end, you cannot make a sub with less capability match up to a better sub.

 

So you can sometimes end up in a bad compromise, where by trying to add more headroom with a 2nd sub you are reducing the capability of the system at least on the low end.  You will increase it's ability above the rolloff point, but below the lesser subs rolloff you will have compromised.

 

DDJ's subs for example, are not a mix of low end subs, decent subs and then a few big subs.  They are all immensely capable and all capable of playing down to the range DDJ wants, even though they are different in significant ways.

 

In some cases, subs are used nearfield, or as "fill-in" subs.  Nearfield goes behind the listening position, and is not normally integrated with the purpose of matching the entire subwoofer range.  Fill-in subs are sometimes used to fix a dip in response or shore up a spot in the room that doesn't respond well like other places.  I am not talking about using subs for these purposes in my comments (FYI).

 

My caution is simple -- beware adding subs that have vastly different capabilities without understanding what you want out of it first, and knowing whether or not it should lead you  there.  If you are looking for true HT sound, you will find the greatest success using similar or the same capability subs.  If your tastes are more towards music, then you have a lot more flexibility but still face similar constraints.

[RoboKlipsch]

On 1/11/2017 at 11:49 AM, zdude said:

I have a Velodyne HGS18 sub and a Sunfire Jr true subwoofer that I just had the surrounds replaced in (surround was like a truck inner-tube). Not necessarily talking these 2, but if I were to come across a nice quality 12" or 15" sub at a reasonable cost I have considered adding to the HGS / Klipsch home theater I'm putting together in a 30' X 20' room with a 12' peaked ceiling. The Sunfire is part of my wife's surround home theater in the den and would cost me an *** whipping if I snaked her's for my system. Anyway, with knowing how bass waves have a tendency to cancel out each other, would I face a problem? And if so, is there ways to overcome this, possibly by matching with another HGS18 or something very close? Any comments or advice would be greatly appreciated -Thanks.

Since I didn't address the original question directly I wanted to here.....

 

simplest answer I would offer is, no, you do not need another HGS18 which at this point are harder to find in good shape, and expensive still.  (I saw one here in Chicago for around $1000 recently).  But what you want is something that can do something similar.

 

If what I understand about the HGS18 system is true, where it has a feedback system that allows for a flat response at least in a perfect room, then a good fit for this is another sub with similar low-end capability that also has built in PEQ of it's own, like the HGS18.  One line that comes to mind is SVS, where their larger ported subs would match the HGS18 response well.   I know there are others out there, including a few that even have a similar feedback system as the HGS, but I am not familiar enough with them and have not heard them so I cannot recommend  (REL?  Outlaw?????)

[twistedcrankcammer]

I own two Velodyne HGS-18IIs and a single Velodyne HGS-10. I had one of the 18s and the 10 first, and you absolutely could not tell a difference as to if the 10 was on or not. I put the 10 in my moms system, and I couldn't be happier with the pair of HGS-18s. I have however added two Klipsch KPT-684s for mid Bass reinforcement. Plan is that the KPT-684s have a new owner when he gets around to picking them up. Eventually I want to buy a Klipsch KPT-1802 

 

Roger

[wvu80]

On 1/11/2017 at 9:35 PM, zdude said:

Holtrp, I see you have 4 of the big Dayton 18" subs. What amp did you use, I think they have a couple of options in their catalog? Did you build them yourself or buy them put together. If you built them, did you build your own boxes or use pre-fabbed boxes?

 

Sorry for so many questions but this project is growing my interest more than other options.

For a long time dual 15" was the "standard" size for bass heads.  Now 18 is the new 15. 

 

Over on AVS.com DIY Speakers and Subs forum the de facto standard for "big boy" sub setups is a pair of Ulimax 18 w/ flat pack.  A single Inuke 6000 w/dsp completes the package, $1200 total.  That's $400 x2 for the subs, plus the $400 Inuke.

 

I've built the DA Reference 15" sealed (w/500w plate amp), the less powerful cousin to the Ultimax subs and it is fantastic.  I used the flat pack and it is highly recommend.  I can give you reasons in detail if you want, but the flat packs are the way to go unless you have wood working skills, proper equipment, and enjoy making sawdust.

+++

 

Edit:  Here is a video on putting together the SEOS speaker, which I have also built.  It will show you the design engineering and fit of the subs which are designed the same way.  The same guy (Erich) sells these kits on diysoundgroup.com and he also provides the exact same ones to Parts-Express.